Egg quality and welfare of white-, tinted-, and brown-shell egg layers in three different non-cage housing systems
The objective of this study was to compare the external, internal, and nutritional quality of eggs, and the welfare of non-beak-trimmed hens housed in three different non-cage systems indoor litter floor pens (L), outdoor with pasture access (OP), and outdoor without pasture access (O). The external egg quality was analyzed for egg weight, shape index, specific gravity, incidence of cracked and dirty eggs, and shell colour, whereas the internal egg quality was analyzed for yolk colour, and Haugh units, and the nutritional egg quality was analyzed for n-3 fatty acids, cholesterol, and vitamins A and E. The hen welfare was evaluated using heterophil to lymphocyte ratio, duration of tonic immobility, and incidence of eggs with pink shells, brown spotted shells, or internal inclusions. Four Spanish breeds with different genetic background (white-, tinted-, brown-, and dark brown-shell egg layers) were used. A total of 1,140 fresh eggs and 360 hens were used. Additionally, 96 eggs were chosen to analyze their nutritional quality. Housing system × breed interaction was significant for egg weight (P < 0.001), shape index (P < 0.001), specific gravity (P < 0.001), incidence of cracks (P < 0.01), shell colour (P < 0.001), yolk colour (P < 0.001), and Haugh units (P < 0.001). There was no significant interaction for the incidence of dirty eggs and the nutritional egg quality. The OP housing system had darker yolk colour in all breeds. The O outdoor system only with access to sand had higher incidence of dirty eggs, whereas the L system had lighter shell colour, suggesting a commercial disadvantage of this system to market darker brown eggs. Eggs obtained from OP hens were characterized by a significant higher n-3 and linolenic fatty acid content of yolk. There were no significant differences for cholesterol content, and vitamins A and E. There was no significant interaction for any welfare indicator. The effect of the housing system on the tonic immobility duration was not significant. The effect of the housing system on the heterophil to lymphocyte ratio was significant (P < 0.05), with heterophil to lymphocyte ratio being higher in hens housed in the OP system. Housing effect was significant for the incidence of eggs with internal inclusions (P < 0.001), hens from the O system having lower incidence. Housing system × breed interaction was significant for mortality percentage (P < 0.05), mortality being highest (30%) in the OP system for the Prat breed. Our study with Spanish breeds demonstrated that none of the tested housing systems were in general superior to the other systems, each system having its unique challenges.
| Main Authors: | , , , , |
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| Format: | artículo biblioteca |
| Language: | English |
| Published: |
Verlag Eugen Ulmer
2013
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| Online Access: | http://hdl.handle.net/20.500.12792/5625 http://hdl.handle.net/10261/293045 |
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